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Epidemiology of oral clefts in a large South American sample
1Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Insights
This study analyzed congenital malformations in Latin America, finding cleft lip with or without cleft palate (CL +/- P) prevalence varied by country, unlike isolated cleft palate (CP). CL +/- P cases showed significant differences from controls in various factors.
Area of Science:
- Epidemiology
- Medical Genetics
- Public Health
Background:
- Congenital malformations, specifically cleft lip with or without cleft palate (CL +/- P) and cleft palate (CP), represent significant public health concerns.
- Understanding the prevalence and associated risk factors of these conditions is crucial for targeted interventions.
Purpose of the Study:
- To determine the prevalence of CL +/- P and CP in a large cohort of newborns across Latin America.
- To investigate epidemiologic factors associated with CL +/- P and CP, comparing affected individuals with controls.
Main Methods:
- Analysis of data from 849,381 newborns across 56 hospitals in eight Latin American countries (1967-1981) from the Latin American Collaborative Study of Congenital Malformations (ECLAMC).
- Epidemiologic study comparing cases of CL +/- P and CP with matched controls, examining factors such as sex ratio, twin births, birth weight, survival, birth order, maternal medication use, and maternal illness.
Main Results:
- Global prevalence of CL +/- P was 0.87 per thousand, and CP was 0.13 per thousand.
- CP frequencies were homogeneous across countries and time, while CL +/- P showed geographic heterogeneity without temporal trends.
- CL +/- P cases differed significantly from controls in sex ratio, twin birth frequency, birth weight, neonatal survival, birth order, and maternal factors during early pregnancy.
Conclusions:
- Geographic variations in CL +/- P prevalence suggest distinct underlying etiologies or environmental influences across Latin American countries.
- Epidemiologic differences observed in CL +/- P cases highlight multifactorial influences beyond genetics, including maternal health and socioeconomic factors.
- Discrepancies with prior research may stem from variations in study design, patient ascertainment, and analytical methods.
Abstract:
A total of 849,381 newborn children were examined during the years 1967 to 1981, in 56 hospitals of eight countries, in the Latin American Collaborative Study of Congenital Malformations (ECLAMC). Of these, 741 had a cleft lip with or without a cleft palate (CL +/- P), yielding a global prevalence of 0.87 per thousand, and 115 had cleft palate (CP) only (frequency: 0.13 per thousand). CP frequencies by country and by year were essentially homogeneous, but those for CL +/- P showed heterogeneity by country (but no temporal trends). Patients thus ascertained, with matched, appropriate controls, have been subjected to a detailed epidemiologic study. For CP, only the sex ratio deviated from the control values; but for CL +/- P the marked divergence in sex ratio was accompanied by differences in the two series on the frequency of twin births, birth weight, neonatal survival, birth order, medicine use, and occurrence of acute or chronic illnesses during the first trimester of pregnancy. Lack of agreement of these results with previous data may be due to different types of patient ascertainment, sample sizes, and methods of analysis.